Incumbent Nicolas Sarkozy and Socialist challenger François Hollande powered through a last day of media appearances and stump speeches Friday ahead of the close of French presidential campaigning at midnight. The rivals largely echoed the attacks and barbs that flew during their Wednesday debate, as they struggled to lure the 44% of voters who backed candidates eliminated in the first round of balloting April 22 to their side. By day’s end, the intensity of insult and allegation flying between conservative and Socialist camps was such that some on-lookers were relieved to see campaigning end before either side thought to call for a repeal of France’s handgun ban.

So who’s favored within that caustic din heading into the May 6 run-off? Indisputably Hollande, who seemed to gain momentum in the final push towards May 6 voting. Yet despite that advantage, neither his supporters—nor those of underdog Sarkozy—are prepared to call the race over.

“I am reasonably confident [of winning] based on François Hollande’s victory in the first round, and due to other positive factors that have arisen since,” said Hollande campaign director, Pierre Moscovici, during a small press gathering Thursday “But I’m [only] reasonably confident, because despite all that has happened up to now, it’s the French people who will determine who wins. And they won’t make that decision until Sunday.”

In other words, there’s every reason for Hollande to anticipate becoming France’s first Socialist president in 17 years—though no one will risk a Gallic “Dewey Defeats Truman” twist of fate by taking anything for granted. Following are reasons why Team Hollande’s optimism is merited—but also guarded.

Polls: The final round of opinion surveys before the run-off show Hollande winning by 5.5% to 6%—a lead he’s enjoyed since becoming the Socialist candidate in October. However, Sarkozy backers stress Hollande’s advance has continued dropping from its all-time height of 58% in late January to the current crooked number. However analysts warn that, for the President to prevail, he’ll need backing of at least 80% of the 6.4 million people who cast first-round votes for extreme-right leader Marine Le Pen. Despite his overt efforts to woo the Le Pen electorate, polls indicate less than half of it is answering his call. Meantime, with voter participation April 22 having exceeded a lofty 80%, an unexpected surge of stay-at-home voters turning out in favor of Sarkozy in the final is improbable.

(Anti) Endorsements: Sarkozy has long wagered his re-election on recapturing the same majority of extreme-right voters who were key to his 2007 presidential win. That bet faces longer odds this time. Not only is that electorate now largely snubbing his call, but Le Pen herself remains vocally hostile to Sarkozy’s return to power. On May 1 she told followers she’d cast a blank ballot in the final—damning him as no better than Hollande. Yet she’s also sent out clear anti-Sarkozy vibes to her voters by reserving her fiercest attacks for the unpopular President.

Perhaps just as bad, Sarkozy’s bow to the extreme-right has sparked controversy across France’s political mainstream, and discomfort even within the president’s ranks. One result of that pandering is that centrist voters whose support is also essential to Sarkozy’s re-election are fleeing him in disgust. On Thursday evening, centrist leader François Bayrou—who finished fifth in first round polling with 9.1%—joined other officials in his Mouvement Démocrate party who earlier said they’d vote for their habitual foe, Hollande. In doing so, Bayrou made his reasoning clear:

“The line that Nicolas Sarkozy has chosen is violent, it’s in contradiction with our values, with the values of Gaullism, [and] with those of the republican right,” Bayrou said, referring the tradition of mainstream conservatives to shun the extreme-right as a xenophobic, anti-European, illegitimate political force. “I can’t cast a blank ballot because that would be no decision, and in these circumstances, indecision is impossible. All that remains is to vote for François Hollande.”

That sort of reaction to what Bayrou called Sarkozy’s “running after the extreme-right” also explains why Sarkozy finds himself getting no endorsements from other candidates eliminated in the first round. That contrasts the backing Hollande received from ousted leftist contenders prior to Bayrou’s support.

“This is the first time in history an incumbent candidate has gotten no endorsements,” Moscovici notes; Sarkozy’s second place finish April 22 marked the first time ever a sitting president didn’t come top in first round voting.

Debate Deflate: Given Hollande’s considerable poll lead, virtually all observers were in agreement heading into Wednesday’s presidential debate that Sarkozy had to score a resounding win to give his re-election hopes the lift they so badly needed. Many expected Hollande to be battered. Sarkozy has always excelled at frontal clashes and verbal brawls, and his status as incumbent promised to establish him as a more credible, experienced leader than Hollande. Instead, most people scored the encounter a draw—which in the current context is tantamount to a Sarkozy defeat. Voter intention since the debate has scarcely moved, much less jumped dramatically to help Sarkozy close the gap with Hollande.

Taken together, those factors add up to one steep hill Sarkozy must climb by Sunday if he hopes to stay in office. That’s quite improbable, but not impossible—especially with the intentions of Le Pen’s volatile base notoriously difficult to gauge. But if just enough doubt remains to dissuade French dailies from printing “Hollande Defeats Sarkozy” headlines in advance, most probably have such a front-page already mocked-up.